Process for the formation of polymer images

ABSTRACT

Process for forming a polymer image by contacting at least one of o-dioxybenzene, o-aminophenol, o-phenylenediamine, pyrogallol or derivatives thereof with a silver halide photographic layer having a photographic latent image in the presence of a polymerizable vinyl compound and sulfite ions to polymerize the vinyl compound selectively at those areas containing the latent image.

United States Patent 1191 Hayakawa et al.

Feb. 5, 1974 PROCESS FOR THE FORMATION OF POLYMER IMAGES Inventors:Yoshihide Hayakawa; Masato Satomura, both of Asaka, Japan Fuji PhotoFilm Co., Ltd., Minami-Ashigara-shi, Kanagawa, Japan Filed: Feb. 24,1972 Appl. No.: 232,316

Related US. Application Data Continuation of Ser. No. 873,710, Nov. 3,1969, abandoned.

Assignee:

Foreign Application Priority Data Nov. 2, 1968 Japan 43-80115 Us. Cl.96/48 R, 96/35.l, 96/115 P1 1111. c1 G030 1/68, G030 1/70 Field ofSearch 96/351, 48, 115 P [5 6] References Cited UNITED STATES PATENTS3,019,104 1/1962 Oster 96/29 3,585,030 6/1971 Pelz et al. 2,887,3765/1959 Tupis 96/35 Primary Examiner-Ronald H. Smith Attorney, Agent, orFirm-Sughrue, Rothwell, Mion, Zinn and Macpeak [5 7] ABSTRACT 30 Claims,No Drawings PROCESS FOR THE FORMATION OF POLYMER IMAGES This is acontinuation of application Ser. No. 873,710, filed Nov. 3, 1969 and nowabandoned.

BACKGROUND OF THE INVENTION 1. Field of the Invention- The presentinvention relates to a process for the formation of polymer images andmore particularly to a process for selectively forming polymer images atareas corresponding to photographic latent image-bearing areas by theactions of a photographic silver halide emulsion and a reducing agent.

2. Description of the Prior Art There have been proposed variousprocesses of forming images by the formation .of highly polymerizedcompounds by photopolymerization of vinyl compounds. It has also beenproposed to directly cause photopolymerization using silver halide as acatalyst (cf,: British Patent No. 866,631: S. Levinos et al.,Photographic Science & Engineering; Vol. 6, 222-226 1962)). It isconsidered, in this reaction, that the photoinduced-decompositionproduct of silver halide serves directly as a polymerization catalystand the light-sensitivity of the reaction does not reach the level whichis easily attained by ordinary development of silver halide particles.

It has also been proposed to form imagewise highly polymerized compoundsby polymerizing vinyl compounds using as a catalyst a silver image orunreacted silver halide after development of an exposed silver halideemulsion with an ordinary developing solution. (cf.: Belgian Patent No.642,477). This procedure has the disadvantage that the development andthe polymerization process must be conducted separately.

It is theoretically of great interest to cause the polymerization ofvinyl compounds by the oxidation product or an intermediate thereofformed in the course of the development of a photographic silver halideemulsion by a reducing agent in the presence of the vinyl compounds,since it can be expected that, in such a procedure, the polymerizationwill be affectedby both an amplification effect of development and anamplification affect of chain polymerization. It has been proposed tocause such a reaction, using as the reducing agent a so-called benzenoidcompound having at least two hydroxyl groups, amino groups,alkyl-substituted amino groups, or aryl-substituted amino groups in theorthoor para-positions with respect to each other on the benzene ring(cf: US. Pat. No. 3,019,104; G. Oster; Nature; Vol. 180, 1275 (1957)).

Moreover, other investigators have reported that they could not succeedin reproducing the experiments of the procedure (S. Levinos and F.W.I-I. Mueller; Photographic Science & Engineering; Vol. 6, 222 l962)).

The aforesaid patent does not indicate any differencebetween thepara-substitutedand the ortho-substituted compounds and in the examplesof the patent, only the para-substituted compounds are'used.

Applicants, however, have found that there are remarkable differencesbetween the use of the orthosubstituted compounds and the use of theparasubstituted compounds; that is, under conditions causing nopolymerization inthe case of using the para;

substituted compounds, the ortho-substituted compounds can serve asinitiators of development and polymerization simultaneously. Further, ithas not been found under any conditions that the para-substitutedcompounds cause development and polymerization at the same time.I-Iydroquinone, one of the parasubstituted compounds and the oxidationproductsthereof are well known compound polymerization in- .hibitors andeven when such compounds are used in high concentrations, thepolymerization occurs to only a very slight extent.

SUMMARY OF THE INVENTION An object of the present invention is toconvert, by-

a simple procedure, a latent image, formed by the irradiation withelectromagnetic waves or particle rays, into a high molecular weightcompound image.

A further object of the present invention is to provide a polymer imagehaving desirable properties for recording or printing by utilizing theabove procedure.

Applicants have discovered that the polymerization of a vinly compoundmay be caused by reducing a silver halide in the presence of the vinylcompound and/or sulfite ions with o-dioxybenzene, o-aminophenol, ophenylenediamine, pyrogallol or a derivative thereof as disclosedhereinafter.

Moreover, it has been found that when a silver halide photographicemulsion is used as the silver halide in the aforesaid procedure, thereaction proceeds more rapidly where the fine crystals of the silverhalide grains contain centers of development. Accordingly, by selectingproper reaction conditions and reaction time, the polymerization can beeffected selectively only in those areas of the layer where silverhalide particles having centers of development exist.

DETAILED DESCRIPTION OF THE INVENTION group, R represents a hydrogenatom or an alkyl group, R4 represents a hydrogen atom or amethoxycarbonyl group, and R and R may be connected to another ringthrough an ether-bonded oxygen atom or carbonyl group;

Formula II (o-aminophenol and its derivatives):

HO RI wherein R represents a hydrogen atom or a hydroxyl group and Rrepresents a hydrogen atom or an amino group; and

Formula 111 (o-phenylenediamine and its derivatives):

HzN H HzN R4 wherein R, represents a hydrogen atom, an alkyl group or anamino group.

By photographic latent image it is meant an invisible imagelike areaformed on a silver halide photographic emulsion layer by the action ofelectromagnetic waves or particle rays and which can be converted into avisible image by development. In an ordilayer and then removing thedevelopment centers by,

the irradiation with electromagnetic waves or particle rays (cf.: Jamesand Huggins; Fundamentals of Photographic Theory"; 2nd edition,paragraphs 3 and 4 (1960), published by Morgam & Morgam Co.).

In the present invention, there may be used an ordinary silver halideemulsion that forms centers of development in the areas irradiated byelectromagnetic waves or particle rays providing negative images bydevelopment, and there may also be employed the socalled direct positivesilver halide emulsion that forms less development center-bearing areasat the emulsion layer subjected to imagewise exposure.

In the present invention, a silver halide photographic emulsion which istreated by an ordinary development process may be conveniently used asthe silver halide emulsion providing negative images. That is, silverchloride, silver bromide, silver chlorobromide, silver iodobromide, andsilver chloroiodobromide photographic emulsions may be employed. Achemical sensitization and/or optical sensitization which is applicableto ordinary photographic emulsions can be applied to the silver halidephotographic emulsion for the purposes of the present invention.Examples of applicable chemical sensitization would be sulfur or noblemetal sensitization (cf.: P. Glafkides; Chimie Photographique; 2ndedition, Photocinema Paul Montel, Paris, 1957, pages 247-301). Asexamples of optical sensitization may be mentionedoptical sensitizersordinarily employed for photographic emulsions, such as cyanine dyes andmerocyanine dyes (see, for example, Kikuchi et al.; Kagaku ShashinBenran" (Handbook of Scientitle Photography), Vol. II, 15-24 (1959),published by Maruzen Co.). Moreover, the silver halide photographicemulsions of the. present invention may also contain stabilizers asemployed in conventional-photographic techniques.

A direct positive silver halide emulsion which can be employed in thepresent invention may be prepared, for example, by solarizatiom Herscheleffect, Clayden effeet or Sabatier effect. These effects are explainedin Chapters 6 and 7, by C. E. K. Mees, of The Theory of the PhotographicProcess; 2nd edition, published by McMillan Co., 1954.

For preparing a direct positive silver halide photographic emulsion bysolarization, a silver halide emulsion layer susceptible to solarizationis prepared and then subjected to uniform exposure to light or to achemical action to render it developablewithout imagewise exposure. Themethods of preparing such silver halide emulsions are disclosed in, forexample, the specifications of British Patent Nos. 443,245 and 462,730.

The Herschel effect is produced by exposing to a light of longer wavelength a photographic emulsion which has been rendered developable by auniform exposure to light of shorter wave length or a uniform action ofa chemical agent. In this case, it is preferable to employ a silverhalide emulsion containing silver chloride for the most part and to usea desensitizing dye such as pynakryptol yellow or phenosafranine forenhancing the effect. Methods of preparing direct positive silver halideemulsions utilizing the Herschel effect are disclosed in, for instance,the specifications of British Patent No. 667,206 and US. Pat. No.2,857,273.

In order to obtain directly a positive image by utilizing the Claydeneffect, it is necessary to subject a silver halide emulsion to overallexposure to light ofa relatively low intensity after imagewise exposureto light of a high intensity for a short period of time, and the areasof the emulsion layer which have not been exposed to the high intensitylight become developable after this overall exposure. g

The Sabatier effect is produced by subjecting a silver halide emulsionlayer to an imagewise exposure and thereafter subjecting the emulsionlayer to an overall exposure while the emulsion layer is immersed in adeveloper or subjected to the action of a chemical reagent to providedevelopability to the areas which have not been subjected to theimagewise exposure.

The Clayden effect and the Sabatier effect can be readily andpractically produced in silver halide emulsions that have a tendency ofyielding centers of development by the first exposure in the innerportions rather than the surface portions of the silver halide.

The methods of preparing silver halide emulsions having a tendency toprovide internal centers of development are disclosed in thespecifications of, for instance,

US. Pat. Nos. 2,592,250 and 2,497,876; and British 1,011,062; and GermanPatent No.

Patent No. 1,207,791.

The photographic emulsion as mentioned above consists of a dispersionsystem in which the particles of silver halide are dispersed in asolution of a high molecular weight material. As the high molecularweight material, gelatin is widely used, although synthetic highpolymers such as polyvinyl alcohol, polyvinyl pyrrolidone, andpolyacrylamide as well as derivatives of natural high polymers such ascarboxymethyl cellulose,

cellulose oxyethyl ether, and dextran may be employed, either alone orin mixtures with gelatin (of: F. Evva; Zeitschrift fur WissenschaftlichePhotographic, Photophysik and Photochemie; Vol. 52, 1-24 (1957)).

Examples of the o-dioxybenzenes, o-aminophenols, o-phenylene-diamines,and derivatives thereof which are useful in the present invention whichmay be mentioned are catechol, 4-methylcatechol, 4-t-butyl catechol,pyrogallol, methyl gallate, pyrogallol red, 0- aminophenol, amidol,Z-aminoresorcinol, ophenylenediamine, tolylene-3, 4-diamine, 1,2,4-triaminobenzene, alizarine, and the like.

These compounds may either be prepared by well known methods or arecommercially available.

In the present invention, silver halide is used in the form of a silverhalide photographic emulsion layer to increase the difference inreactivity between areas irradiated by electromagnetic waves or particlerays and areas not irradiated, that is, to increase the selectivity ofreaction.

Oxidation of the reducing agent used in the invention, for example,4-t-butyl catechol, is reported in T.J. Stone & W. A. Waters; Journal ofChemical Society, 1488 (1965 wherein the reducing agent was treated withferric salt under alkaline conditions and the measurement of theelectron spin density on the ring at the oxidation intermediate wasdetermined.

The oxidation of catechol is also reported by the above researchers inJournal of Chemical Society; 408 (I964).

According to their speculations, the reaction is considered to proceedas follows:

The reaction mechanism for the initiating of the poly merization ofvinyl compounds as the result of the reduction of silver halide by theaforesaid compounds in the present invention has not yet been cleared orcompletely determined. However, it is generally considered that thepolymerization proceeds by a free radical mechanism since a compoundcapable of causing free radical polymerization can be utilized in thereaction and the reaction proceeds in an aqueous solution and that afree radical polymerization inhibitor retards the reaction.

it has not yet been confirmed whether free radicals are formed directlyby the reaction of the compound in the present invention with a silverhalide, or whether free radicals are formed by action with water,oxygen, etc., in the reaction system. However, although the influence ofoxygen is unknown from the aforesaid publications, it is generallyconsidered that the reaction occurs as follows:

OH 0- o 0- OH- Z Z R R R R (-bl (etc- The radical represented by (l-a)or (l-b) described above is pre-sumed to initiate the polymerization.

Also, when a vinyl compound is added to the reaction system afterreducing silver halide particles irradiated by electromagnetic waves orparticle rays with the compound of this invention, the occurrence ofpolymerization is not observed. Thus, it is clear that thepolymerization of the vinyl compound occurs at the same time the silverhalide is reduced. It is, therefore, considered that an intermediateproduct of the silver halide and the compound of the present inventioncontributes to the reaction.

Furthermore, when the reaction is stopped after a proper period of time,a high molecular weight compound is formed selectively only at the areasirradiated, but when the above reaction is further continued, the highmolecular weight compound is formed also at the areas which have notbeen irradiated. These facts are considered to be caused by thedifference in reactivity between the irradiated silver halide andunirradiated silver halide.

However, the phenomena of high molecular weight compound formation atboth unexposed and exposed areas when the reaction is continued for alonger period of time is similar to the phenomena termed fog, whichoccurs when development is continued for a longer period of time inordinary photographic processes and in which the whole silver halidephotographic emulsion layer becomes blackened. Hence the aforesaidproblem does not affect the practicability of the present invention.

When p-aminophenol or hydroquinone are used in substantially the sameconcentration as that of the reducing agents of the present invention,development occurs, but no polymerization of vinyl compound occurs. Thisfact is considered to result from the fact that the stability of asemiquinone radical, formed by the reaction of the reducing agent andsilver halide, is extremely different as between the p-substituted andthe o-substituted compounds. As is well known, hydroquinone is apolymerization inhibitor as well as being a well-known developing agent.Catechol, which is one of the reducing agents which may be used in thepresent invention, is also used as a developing agent, but when it isused as a reducing agent in a low concentration and under alkalineconditions, as in the present invention, the semiquinone radical formedis very unstable (the aforesaid report also teaches that the semiquinoneradical of catechol is readily dimerized) and hence the radical isconsidered to act merely as an initiator for the polymerizationreaction.

Although the pH of the reaction system and the concentration of thereducing agent are not generally defined, the development andpolymerization can be conducted in even a higher concentration of thereducing agent as the content of amino group is raised, which isconsidered to be based on the difference in stability between theintermediate products formed by oxidation.

As a process for forming an image of a high molecular weight material byutilizing the light sensitivity of silver halide, there is known aso-called tanning developing process wherein the cross-linking ofgelatin is effected by the oxidation product of a well-known developingagent. However, in this known process, the image formed is limited tothe areas where the gelatin is cross linked. On the other hand, in thepresent invention, polymer images having various desired properties canbe obtained in accordance with the vinyl compounds to be employed, andthus various desirable properties such as dyeing properties and chemicalresistance, which have never been obtained by the process of crosslinking gelatin, can be obtained, which is a feature of the presentinvention.

Moreover, applicants have found that in the process of the presentinvention the polymerization of vinyl compounds can be accelerated whensulfite ions are present in the reaction system.

Sulfite ions may be added to the reaction system either in the form of acompound originally having the sulfite ions, such as alkali metal-orammonium sulfite or alkali metal or ammonium bisulfite, or in the formof a compound which will give sulfite ions as a result of hydrolysis,such as pyrosulfites of alkali metals or ammonium or the adducts ofbisulfites with aldehydes such as formaldehyde or glyoxal. Theappropriate amount of sulfite ions to be added depends upon the kind andamount of reducing agent and the vinyl monomer to be used and the pH ofthe reaction system.

More than 0.05, especiallymore than 0.2 mole per liter of the system hasgenerally been found to be effective.

It is well know to add a sulfite to a photographic developing solution.It is believed that the sulfite prevents the auto-oxidation of thedeveloping agent and the occurence of uneven development by reactionwith the oxidation product of the developing agent, such as hydroquinoneor p-aminophenol (of: for example C. E. K. Mees, The Theory of thePhotographic Process; 2nd edition, page 652; published by McMillan Co.1954)). It should be noted that since the intermediate product of theoxidation of the o-dioxybenzene, oaminophenol, o-phenylenediamine,pyrogallol, or a derivative thereof by silver halide initiates thepolymerization of vinyl compounds in the process of the presentinvention, the polymerization accelerating action of the sulfite ions isessentially different from the action of removing the oxidation productsas in ordinary developing solutions as mentioned above. Thepolymerization would be inhibited, rather than acceler ated, if thesulfite simply removed the oxidation product.

While the mechanism of the action of sulfite ions in the process of thepresent invention is not yet clear, it would appear that the sulfiteions prevent the polymerization inhibiting action of oxygen.

The vinyl compounds to be employed in the present invention includescompounds which are either liquid or solid at room temperature and arecapable of addition polymerization and mixtures thereof. Examples ofsuch vinyl compounds are acrylamide, acrylonitrile,N-hydroxymethylacrylamide, methacrylic acid, acrylic acid, calciumacrylate, sodium acrylate, N-t-butyl acrylamide, methyl methacrylate,methyl acrylate, ethyl acrylate, vinylpyrrolidone, vinylmethyl ether,vinylbutyl ether, vinyl isopropyl ether, vinyl isobutyl ether,

vinyl butyrate, 2-vinylpyridin e fl vinylpyridine Z-methyl-N-vinylimidazole, potassium vinylbenzene sulfonate, and vinyl carb azole dicyclopentadiene methacrylate For the present invention, compbunds 1tioned above. Examples of such compounds areN N methylene-bisacrylamide.ethylene glycol dimethacrylate. diethylene glycol dimethacrylate.triethylene glycol dimethacrylate polyethylene glycol dimethacrylate.divinyl ether. divinyl benzene. bisphenol-A- dimethacrylate.butylene-dimethacrylate. pentaeryth- -ritol tetraacrylate and the like.

Although it is convenient for the present invention to employwater-soluble vinyl compounds, waterinsoluble vinyl compounds may beemployed by adding the vinyl compound as an emulsion to the reactionsystem. The emulsification of the water-insoluble vinyl compound may beconducted by a suitable stirring means in the presence of a surfaceactive agent and/or a high molecular weight compound in accordance withconventional practice.

Any of electromagnetic waves or particle rays to which ordinaryphotographic emulsions are sensitive may be used in the presentinvention. For example, visible rays, ultraviolet rays, infrared rayshaving wave lengths of shorter than 1.3 microns, X-rays, gamma rays,electron beams, and alpha rays can be used.

In carrying out the present invention, it is necessary to conduct twosteps or irradiation by electromagnetic waves or particle rans and ofreduction and polymerization. In particular, for the recording ofimages, it is de sirable that the silver halide particles change theirpositions little during the period between the irradiation and thepolymerization of the vinyl compound in the reaction system.Accordingly, it is desirable that the reaction system be maintained in ahighly viscous liquid or in a gel state-While photographic emulsionshave some viscosity and are susceptible to gelation since they containnatural or synthetic high molecular weight material, an additionalmolecular weight material may. be added to the emulsion if the viscositythereof is insufficient.

For the purpose or irradiating the silver halide particles, they may bedispersed in an aqueous solution or held in a dry gel. That is, a highlyviscous or gelled photographic silver halide emulsion on a suitablesupport may be subjected to the irradiation either in the dried state orthe undried state. As the reduction and polymerization take place at thesame time, the reduction must be conducted in the presence of the vinylcompound. Furthermore, in the present invention, the ortho-typebenzenoid developing agent, which acts as the reducing agent for silverhalide may be present in the silver halide emulsion together with thevinyl compound, or either one may be incorporated preliminary in thesilver halide emulsion and, after irradiation, the other may be added tothe system. Moreover, both of them may be added to the system afterirradiation.

.The combined reduction and polymerization reaction requires thepresence of water and accordingly the reaction must be conducted in anaqueous solution or in a humid gel state.

The reaction of the present invention proceeds'well in an alkalinestate. The optimum pH value of the system depends upon the kind andconcentration of the silver halide, the reducing agent, and the highmolecular weight material used asmedium or binder, as well as thereaction temperature, but the reaction is generally carried out at a pHof higher than about 6, in particular, higher than 7.

When using the photographic silver halide emulsion coated on a support,the reaction can be conducted by immersing the ligh-sensitive elementformed, after irradiation, in an alkaline aqueous solution. It isconvenient to incorporate the reducing agent or the vinyl compound inthe alkaline aqueous solution.

Although the reaction is readily stopped by adjusting the pH of thesystem to acidity, e.g., less than 5, the reaction may also be stoppedby cooling, removing the reactants by washing, dissolving the silverhalide by a fixing solution for photographic processing, or adding apolymerization inhibitor to the reaction system.

When the high polymer which forms the medium for silver halide and themonomeric vinyl compound are coated as a layer, it is desirable toincorporate a small amount of a thermal polymerization inhibitor in thelayer in order to prevent the spontaneous over-all thermalpolymerization of the vinyl compound before processing. As such thermalpolymerization inhibitors, any of the compounds that are known asthermal polymerization inhibitors in ordinary free radicalpolymerization may be utilized: for example, p-methoxyphenol,hydroquinone, alkylhydroquinone, 2,6-di-t-butyl-pcresol, and the like.

In the case of preliminarily incorporating the vinyl compound in thereaction system, the weight of the vinyl compound to be used should be1/30 to 30 times, preferably A to 4 times the weight of the highmolecular weight material to be used preliminary. The weight of thesilver halide to be used should be 1/20 to 2 times, preferably l/lO to/2 times the weight of the high molecular weight material used-Moreover, in the case of incorporating the reducing agent mentionedabove in the reaction system, the amount of the reducing agent ispreferably l/lOOO to moles per 1 mole of silver halide used.

Also, in the case of employing a thermal polymerization inhibitor, theamount thereof should be about 10 ppm. to l/lOO of the weight of thevinyl compound or compounds to be employed. In the case of adding thevinyl compound or compounds in the processing solution, it is usuallypreferred that the concentration thereof be as high as possible, or theamount to be added in the solution is rather controlled by thesolubility of the vinyl compound in the processing solution.

When the reducing agent used in the present invention is incorporated inthe processing solution, the optimum concentration thereof depends onthe structure of the reducing agent and the pH of the reaction system,but the concentration is generally l/IOOOO mole to 3 moles, preferablyl/3000 to 1 mole per liter.

As in any ordinary silver halide photographic process, there can be anyinterval of time between the irradiation and the polymerization process.In some cases, the effect ofthe irradiation may be reduced to someextent according to the properties of the photographic emulsion'to beused, the conditions and the period of storing the emulsion, and in sucha case, a more desirable effect can be obtained by increasing the amountof the irradiation. In the case of applying the process of the presentinvention to the recording of images, it is possible to make use ofdifferences in solubility, lightscattering properties, tackiness,dye-receptivity and other physical and chemical properties between thevinyl compound and the polymer thereof. By dissolving away theunpolymerized portions after subjecting the system to the irradiationand the polymerization reactions, by utilizing the difference insolubility to leave a polymer image at only the portion irradiated, arelief image can be formed.

In this case, it is preferred that the high molecular weight materialoriginally present in the system be washed away together with theunreacted monomer. For this purpose, it is preferably that the highmolecular weight material originally present in the system be a linear,substantially uncross-linked polymer or, if cross-linked, one that issusceptible to chain fission or break-up of the cross-linkages and thatthe highly polymerized compound formed by the polymerization of thevinyl compound be a cross-linked polymer or a polymer ofthree-dimensional structure. Thus, it is preferred to employ a compoundhaving a plurality of vinyl groups, as mentioned above, either alone orin combination with a compound having one vinyl group. However, it isnot essential to employ a compound having a plurality of vinyl groups,since there are many cases where a great difference in solubility existsbetween the monomer and the polymer formed therefrom, even if the highmolecular weight compound formed is a twodimensional, or linear,water-soluble high polymer, due to the interaction of the compoundformed by the polymerization and the high polymer originally present inthe reactionsystem, for example, polyacrylic acid or gelatin.

The high polymer image formed by the process of this invention can beemployed in various printing processes.

Also the present invention can be utilized for forming colored images ordye images. In this process, the polymerization is conducted using amonomer having a group capable of taking a charge by electrolyticdissociation or the addition of hydrogen cation, and thereafter theimage of the polymer may be selectively dyed by a dye having a charge ofa polarity opposite to that of the polymer. Moreover, the colored imagethus obtained can be transferred ,to other supports by various methods.

As such addition-polymerizable vinyl compounds which can be charged byelectrolytic dissociation or the addition of hydrogen cation andto beused in the aforesaid color image forming process, there may bementioned the following. As monomers providing a negative charge to thehigh molecular weight compound formed by the polymerization of themonomer, there are vinyl compounds havinga carboxyl group, such asacrylic acid, methacrylic acid, itaconic acid, and maleic acid; vinylcompounds having an ammonium salt or a metal salt of a carboxylic group,such as ammonium acrylate, sodium acrylate, potassium acrylate, calciumacrylate, magnesium acrylate, zinc acrylate, cadmium acrylate, sodiummethacrylate, calcium methacrylate, magnesium methacrylate, zincmethacrylate, cadmium methacrylate, sodium itaconate, and sodiummaleate; vinyl compounds having a sulfonic acid group, such as vinylsulfonate, and p-vinylbenzene sulfonate; and vinyl compounds having anammonium salt or metal salt of sulfonic acid, such as ammoniumvinylsulfonate, sodium vinylsulfonate, potassium vinylsulfonate,potassium p-vinylbenzene sulfonate, and the like. As monomers providinga positive charge to the high molecular weight compound formed from themonomer, there are vinyl compounds having a basic nitrogen atom, such as2-vinylpyridine, 4-vinylpyridine, 5-vinyl-2- 1 1 methylpyridine, N,Ndimethylaminoethyl acrylate, N,N-dimethylaminoethyl methacrylate, N,N-diethylaminoethyl acrylate, and N,N-diethylaminoethyl methacrylate andvinyl compounds having a nitrogen of a quaternary salt formed by thereaction of the bases of the above vinyl compounds and methyl chloride,ethyl bromide, dimcthyl sulfate, diethyl sulfate, or methylp-toluenesulfonate or the like.

These compounds either may be prepared by well known methods or arecommercially available. These compounds may be used alone or incombination. Also, they may be used as a mixture with a water-solubleaddition-polymerizable vinyl monomer having no charge. Examples of vinylcompounds which may be used with the aforesaid vinyl monomers areacrylamide, N-hydroxymethyl acrylamide, methacrylamide, methylmethacrylate, vinylpyrrolidone, N,N- methylenebis(acrylamide),triethylene-glycol dimethacrylate, polymethylene glycol dimethacrylate,and the like. In the case of employing a vinyl compounds having nocharge together with the aforesaid vinyl compound having a charge, therelation between the reactivity thereof and the amount employed shouldbe adjucted so that a high molecular compound containing substantiallyno group capable of being electrolytically dissociated is not formed. I

As dyes capable of being charged by electrolytic dissociation, there aregenerally used ordinary acid and basic dyes. When a vinyl compoundproviding a high molecular weight compound having a negative charge isused, a basic dye is employed, while when a vinyl compound providing ahigh molecular weight compound having a positive charge is used, an aciddye is employed. In other words, as the basic dye has a positive charge,it selectively dyes the high molecular weight compound having negativecharge, whereas as the acid dye has a negative charge, it dyes the highmolecular weight compound having positive charge. Thus, a dye image orcolored image is obtained in conformity to the high molecular weightcompound formed imagewise.

When gelatin is usedas a binder for photographic silver halideemulsions, the isoelectric point of the gelatin should be consideredduring dyeing since gelatin is an amphoteric electrolyte. That is,gelatin has a negative charge at a pH higher than the isoelectric pointof the gelatin which it has a positive charge at a pH lower than theisoelectric point thereof. Accordingly, in the case where a highmolecular weight compound having a negative charge is formed, the highmolecular weight material is dyed by a basic dye at a pH lower than theisoelectric point of gelatine to be used, whereby only 1 the polymerimage can be dyed without dyeing the gelatin. Furthermore, in such acase, the following procedure may be applied. That is, by first dyeinguniformly the surface of the photographic emulsion layer bearing thepolymer image at a pH higher than the isoelectric point of gelatin andthen washing the surface thereof with a solution having a pH lower thanthe isoelectric point, the dye at the areas having no polymer image iswashed away to provide the dyed polymer image.

In the case of dyeing a polymer image having a positive charge with anacid dye, the dyeing may be conducted at a pH higher than theisoelectric point of gelatin. If the pH is too high or too low, thesolubility of dye will be reduced or the electrolytic dissociation ofthe high molecular weight compound to be provided with charges therebywill be disturbed. Thus, although the optimum pH range depends upon thekinds of the vinyl compound, the dye, and the binder, such as gelatin,to be used, it is suitable 2.5-4.5 when an ordinary limetreated gelatinhaving an isoelectric point of about 4.9 is employed and the imageof ahigh molecular weight compound having a negative charge is dyed with abasic dye, while the pH is suitably 5.0-8.0 when the aforesaid gelatinis used and the image of high molecular weight compound having apositive charge is dyed with an acid dye.

Examples of acid dyes which may be employed in the present invention areC.I. Acid Yellow 7 (C.I. 56, C.I. Acid Yellow 23 (C.I. l9, l40) ;C. I.Acid Red 1 (C. I. 18, 050); C. I. Acid Red 52 (C. I. 45, 100); C. I.Acid Blue 9 (C. I. 42, 090); C.I. Acid Blue 45; C. I. Acid Blue 62 (C.I. 62, 045); C. I. Acid Violet 7 (C. I. I8, 055); and the like. Examplesofbasic dyes are C. I. Basic Yellow 1 (C. I. 49, 005); C. I. BasicYellow 2 (C. I. 41, 000); C. I. Basic Red 1 (C'. I. 45, C. I. Basic Red2 (C. I. 50, 240); C. I. Basic Blue 25 (C.I. 52, 025); C. I. BasicViolet 3 (C. I. 42, 555); C. I. Basic Violet 10 (C. I. 45, I70); and thelike.

The C. I. number indicated above is cited from Color Index (2nd edition)and the aforesaid dyes are all commercially available under varioustrade names.

In the practice of the process of this invention, it is necessary toconduct the irradiation and thereafter conduct the reduction andpolymerization.

By washing away the unpolymerized vinyl monomer or monomers afterconducting the irradiation, reduction and polymerization according tothe process of the present invention, a polymer image can be obtained.That is, since the polymer has low solubility as compared with themonomer and also since a high molecular weight material, such asgelatin, originally present in the system as a binderfor the silverhalide photographic emulsion, is left without being dissolved in water,the polymer is only slightly diffused into the gelatin layer, only thepolymerized portions are left to form images. By using a vinyl monomerhaving two or more vinyl groups, the insolubility and the diffusionresistance properties of the polymer can further be enhanced.

By dyeing as mentioned above after conducting the polymerization, acolor image of the polymer image can be obtained. Furthermore, byremoving the silver halide by a fixing procedure and further dissolvingaway the silver image by the action of an oxidizing agent and solventfor the silver salt, a clear and sharp colored image is obtained. When areducing agent having a very high polymerization initiating effect isemployed, a sufficient polymerization reaction .occurs even where a veryslight amount of reduced silver is formed and hence in such acase it isscarcely necessary, if at all, to remove the silver image by oxidation.

In the process of thepresent invention, the dye or colored image formedcan be transferred to another support. The transfer of the dye image iscarried out by wetting the dye image-bearing layer with a solvent fordye, such as methanol, water, or an aqueous solution of an acid, a baseor a salt and closely contacting the layer to a support to which the dyeimage is transferred. As the transfer support, there may beemployedordinary papers, papers coated with a hydrophilic polymer layer or agelatin layer, and films coated with a hydrophilic polymer layer or agelatin layer.

In the case of transferring the dye image onto a support having coatedthereon a gelatin layer, it is convenient to use a support treated witha mordant such as an aluminum salt as used inconventional dye transferprocesses. When a polymer image having a charge is once formed, aplurality of reproductions can be obtained by repeating the dyeing andtransferring as mentioned above. In this case, several copies of thetransferred dye image can be obtained from one dyed image. Also, as alarge number of dyeings can be applied repeatedly from one polymerimage, a large number of reproductions can be easily formed.

The invention will further illustrated by the following examples:

EXAMPLE 1 A photographic light-sensitive film having a gelatino silverchloroiodo-bromide photographic emulsion layer was exposed, processed ina solution containing a reducing agent and sodium acrylate to conductimagewise polymerization, and the polyacrylicacid image thus formed wasdyed with a basic dye.

The photographic light-sensitive film used in the example was preparedas follows: After s'ubcoating the both surfaces of a polyethyleneterephthalate film, the one surface of the film was coated with ananti-halation layer and the other surface thereof was coated with a finegrain gelatino silver halide emulsion containing 0.7 mole of chlorine,about 0.3 mole .of bromine and about 0.001 mole of iodine per 1 mole ofsilver and about 100 g. of lime-treated gelatin per 1 mole of silver andalso having incorporated therein a merocyanine dye having a maximumsensitivity of 550 mg. as a sensitizing dye, muchchloric acid as ahardening agent in an amount of about 1.5 g. per 100 g. of gelatin, andsuitable stabilizer and surface active agent in such thickness that thelayer contained 50 mg of silver per 100 cm. of said layer. Thereafter, aprotective layer consisting of gelatin was further applied to theemulsion layer in a thickness of about 0.8 microns. The photographicfilm was the type 1Q I N sodium hydroxide Sodium methacrylute 75 g.Reducing agent shown in Table l Potassium methabisulfite 3 g. Water 75g.

amount IIECESSUT) IO adjust the pH of the solution to the value I shownin Table 1.

When the exposed photographic film was processed for a period of timeshown in Table I, a faint brown image was formed in the exposed areas.The sample was washed with a 1.5% aqueous solution of acetic acid andthen fixed in a fixing solution having the following composition:

Sodium thiosulfate (anhydrous) 150 g Potassium methabisulfite 15 g Waterto make 1 liter Afterwashingwithwater, the sample was immersed in a 0.1percent aqueous solution of a: red basic dye, Rhodamine 6 G.C.P., (C.I.Basic Red 1) for 5 minutes.

Then, when the sample was washed with a 5 percent aqueous acetic acidsolution for 5 minutes, the dye at the other areas than those having thefaint brown image mentioned above was washed away but the imagebearingportion was colored in red. The faint brown image was a silver image andhence readily removed by a Farmers reducer. By removing the silverimage, a clear and sharp red image was obtained. The removal of thesilver image could be conducted before dyeing. That is, a clear andsharp red imageas above could be obtained by first removing the silverimage and then dyeing the colorless layer.

On these samples, the densities of the exposed portions of the unexposedportions to green light were measured before and after dyeing,respectively, and the results are shown in Table I together with thekinds and amounts of reducing agents, the pH at processing and theprocessing period of time.

Table 1 N0. Reducing (A) (B) (C) (02) (D) (E) agent (C-I) (C-Z) (D-l)(13-2) 1 Catechol 0.05 70 0.06 0.16 0.66 2.40 9.00 2 4-Methy1- catechol0.03 0.08 0.26 0.45 1.19 9.00 3 4-t-Butylcatechol 0.03 70 0.08 0.31 0.481.52 9.00 4 Pyrogallol 0.01 70 0.07 0.26 0.45 1.23 9.10 5 Methyl gallate0.03 70 0.08 0.21 v 0.08 1.18 9.00 6 Pyrogallol red 0.03 70 0.11 0.310.13 2.10 9.00 7 o-Aminophen- '8 Amidol 0.01 70 0.15 0.38 0.27 1.78 9.109 2-Aminoresnrcinol 0.03 30 0.09 0.29 0.14 1.33 9.00 10 o-Phenylenediamine 0.05 70 0.08 0.26 0.08 0.75 9.00 l l Tolylene- 3.4-diamine 0.0370 0.07 0.20 0.08 1.33 9.00 12 1.2,4-triaminobenzene 0.01 30 0.08 0.360.09 1.20 9.00 13 Alizarin 10.80 0.18 0.28 0.15 0.74

(A): amount of reducing agent in grams; (B) processing time in minutes;(D) density ofexposed area;

(C) transmission density of unexposed area; (01) before dyeing; (C-2)after dyeing;

(D-l) before dyeing; (D-Z) afterdyeing; and (E) pH value From the abovetable, it will be seen that the increase in density by dyeing was higherin the exposed portion than in the unexposed portion, that is, theexposed portion was selectively dyed. This fact is also clear from thefact that a sharp red image was obtained by removing the silver imagewith a Farmers reducer. Also as the density of silver image in Sample 1and Sample 1 l was low, a sharp red image was obtained without removingthe silver image.

EXAMPLE 2 The same procedure as in Example 1 was followed using 30 mg.of dimethyl-p-phenylenediamine sulfate, methyl-p-aminophenol sulfate,p-phenylenediamine, or 2-amino-5-dimethylaminotoluene as thep-substituted reducing agent. The composition of the processing solutionwas the same as that of Example 1 except for the reducing agent and theamount thereof and the pH of the solutionwas 9.0. Afterallowing thesample to stand for 10 minutes at 30C., the sample thus processed wassubjected to the after treatment of Example 1. However, the increase ofdensity by dyeing of the image portion was not observed and hence theimage consisted of only the silver image and no polymerization reactionoccured.

EXAMPLE 3 The same procedure as in Example 1 was followed usingp-aminophenol as the reducing agent. As the processing solution was usedone having composition A, B, C, or D shown in the following table.

After being allowed to stand for 15 minutes at C.,

the sample was subjected to the same after treatment as in Example 1. Onobserving the sample before dyeing, it was found that 'a faint brownsilver image was observed on the sample processed in solution A, asilver image was only slightly noticable in solution B, a dense brownimage was formed in solution C, and a very dense brown image wasobtained in'D, although the density was weaker than in the case ofprocessing in solution C.

Thereafter, by processing each sample with dyeing solution andsubjecting it to the treatment, the increase in density by dyeing in adye was not observed, which showed that no polymer was formed.

In addition, when the developing procedure for Sample A- was continuedfurther for 50 minutes, the density of image was increased, but thedensity of image by dyeing was not observed, that is, the formation ofpolymer was not observed. This was also true in the case of employingsolution D.

EXAMPLE 4 The same procedure as in Example 1 Wu followed usingprocessing solutions A or B having the compositions as shown in thefollowing table:

Component A B Sodium methacrylate (g) 75 o-Phenylenediamine (g) l 1Potassium methabisulfite (g) 3 H OlNNaOH solution (ml) 75 75 pH of thesystem 9.0 9.0

This experiment demonstrates the effects of sulfite ions on the process.After being allowed to stand for 20 to 30 minutes at 30C., the processedsample was subjected to the after treatment as in Example 1. In thiscase, an increase in density by dyeing was observed for the sampleprocessed in solution A, which showed the formation ofa polymer image,while in the sample processed in solution B, only the silver image bydevelopment was observed but the formation of polymer was not observed.

The optical density to green light was measured as in Example l, theresults of which are shown in the following table.

Solution (C) transmission density of unexposed area; (C-l) beforedyeing; (C-Z) after dyeing; (D) density of exposed area; (D-l beforedyeing; and (D-Z) after dyeing.

As is clear from the above table, the density of the image before dyeingwas higher in sample B than sample A but the density after dyeing wasvery low in sample B as compared with sample A. Moreover, the sample B,that is, the sample processed in processing solution B, was processedfor a longer period of time, the increase in density of imageby dyeingwas lower than that of sample A.

What is claimed is:

l. A process for forming a polymer image which comprises exposing aphotographic silver halide emulsion layer so as to provide a latentimage and subsequently developing said latent image with at least onecompound selected from the group consisting of an odihydroxybenzene andits derivatives represented by the general formula (I) HO RI wherein Rrepresents a hydrogen atom or a hydroxyl group, R represents a hydrogenatom or an alkyl group, and R represents a hydrogen atom or amethoxycarbonyl group; an o-aminophenol and its derivatives representedby the general formula (II) H sN Ra HO RI H (II) wherein R represents ahydrogen atom or a hydroxyl group and R represents a hydrogen atom or anamino group; and .an o-phenylenediamine and its derivatives representedby the general fromula (Ill) wherein R represents a hydrogen atom, analkyl group or an amino group in the presence of at least one compoundselected from the group consisting of addition-polymerizable vinylidenemonomers and addition-polymerizable vinyl monomers and in the presenceof sulfite ions, whereby said monomer is polymerized at thelatent-bearing areas of the emulsion layer.

2. A process in accordance with claim 1 which additionally comprisesdyeing the polymer image thus formed with a dye which has a chargeopposite to the charge of the image polymer when the dye iselectrolytically dissociated.

3. The process of claim 2, wherein, said polymer stems from a monomerhaving a negative charge, said monomer selected from the groupconsisting of vinyl compounds having a carboxyl group, vinyl compoundshaving an ammonium salt or metal salt of a carboxylic group, vinylcompounds having a sulfonic acid group,

and vinyl compounds having an ammonium salt or metal salt of sulfonicacid.

4. The process of claim 2, wherein said polymer stems from a monomerhaving a positive charge, said monomer being a member selected from thegroup consisting of vinyl compounds having a basic nitrogen atom andvinyl compounds having a nitrogen atom of a quaternary salt.

5. The process of claim 2, wherein a water-solubleaddition-poly-merizable vinyl monomer carrying no charge may be used incombination with the charged monomer serving as the polymer imageprecursor.

, 6.'The process of claim 5, wherein said water-solubleaddition-polymerizable vinyl monomer is a member selected from the groupconsisting of acrylamide, N- hydroxymethyl acrylamide, methacrylamide,methyl methaerylate, vinylpyrrolidone, N,N-methylenebis (acrylamide),triethylene-glycol dimethacrylate, and polymethyleneglycoldimethacrylate.

7. The process of claim 2, wherein said dye is an acid dye and a memberselected from the group consisting of Acid Yellow No. 7, Acid Yellow No.23, Acid Red No. 1, Acid Red No. 5 2, Acid Blue No. 9 Acid Blue No. 45,Acid Blue No. 62, and Acid Violet No. 7.

8. The process of claim 2, wherein said dye is a basic dye and a memberselected from the group consisting of Basic Yellow No. 1, Basic YellowNo. 2, Basic Red No. 1, Basic Red No. 2, Basic Blue No. 25, Basic VioletNo. 3, and Basic Violet No. 10.

9. The 'brbe'siifaim'iifilerein said compound is a member selected fromthe group consisting of catechol, 4-methylcatechol, 4-t-butyl catechol,pyrogallol, methyl gallate, pyrogallol red, o-aminophenol, amidol,2-aminoresorcinol, o-phenylenediamine, tolyene-3, 4- diamine,l,2,4-triaminobenzene and alizarine.

10. The process of claim 1, wherein the high molecular weight materialmaintained in the silver halide emulsion layer is gelatin.

11. The process of claim 1, wherein the high molecu lar weight materialmaintained in the silver halide emulsion layer is a member selected fromthe group consisting of polyvinyl alcohol, polyvinyl pyrrolidone,polyacrylamide, carboxymethyl cellulose, cellulose oxyethyl ether, anddextran, or mixtures of the same with gelatin.

12. The process of claim 1, wherein said sulfite ion stems from aprecursor selected from the group consisting of an alkali metal,ammonium sulfite, an alkali metal bisulfite, and ammonium bisulfite.

13. The process of claim 1, wherein said sulfite ion stems from aprecursor capable of yielding sulfite ions upon hydrolysis, saidprecursor being a member selected from the group consisting ofpyrosulfites of alkali metals, ammonium pyrosulfites, and adducts ofbisulfites with aldehydes.

14. The process of claim 13, wherein said aldehyde is a member selectedfrom the group consisting of formaldehyde and glyoxal.

15. The process of claim 1, wherein said sulfite ion is present in anamount greater than 0.05 mole per liter of reaction system.

16. The process of claim 1, wherein said sulfite ion is present in anamount greater than 0.2 mole per liter of reaction system.

17. The process of claim-1, wherein said vinyl compound is a memberselected from the group consisting of acrylamide, acrylonitrile,N-hydroxymethylacrylamide, methacrylic acid, acrylic acid, calciumacrylate, sodium acrylate, ethyl acrylate, vinylpyrrolidone, vinylmethylether, vinylbutyl ether, vinylisopropyl ether, vinylisobutyl ether,vinyl butyrate, 2- vinylpyridine, 4-vinylpyridine, Z-methyl-N-vinylimidazole, potassium vinylbenzene sulfonate, and vinyl carbazoledicyclopentadiene methacrylate.

18. The process of claim 1, wherein said vinyl compound is a memberselected from the group consisting of N,N'-methylene-bisacrylamide,ethylene glycol dimethacrylate, diethylene glycol dimethacrylate,triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate,divinyl ether, divinyl benzene, bisphenol-A-dimethacrylate,butylene-di-methacrylate, and pentaerythritol tetraacrylate.

19. The process-of claim 1, wherein said process is carried out at a pHof greater than about 6.

20. The process of claim 1, wherein said process is carried out at a pHof greater than 7.

21. The process of claim 1, further comprising the presence of a thermalpolymerization inhibiting amount of a thermal polymerization inhibitor.

22. The process of claim 21, wherein said inhibitor is a member selectedfrom the group consisting of pmethoxyphenol, hydroquinone,alkylhydroquninone, and 2,6-di-t-butyl-p-cresol.

23. The process of claim 21, wherein said polymerization inhibitor ispresent in an amount of from 10 ppm to l/OO ppm of the weight of saidvinyl compound.

24. The process of claim 1, wherein said vinyl compound is present in anamount of from l/30 to 30 times the weight of the high molecular weightmaterial of the silver halide emulsion.

25. The process of claim 24, wherein the vinyl compound is present in anamount of from A. to 4 times the is present in an amount of from 1/1000to 20 moles per mole of silver halide.

29. The process of claim 1, wherein said compound is present in aprocessing solution, in a concentration of from l/l0,000 to 3.0 molesper liter of solution.

30. The process of claim 29, wherein said concentration ranges from1/3000 to 1 mole per liter.

2. A process in accordance with claim 1 which additionally comprisesdyeing the polymer image thus formed with a dye which has a chargeopposite to the charge of the image polymer when the dye iselectrolytically dissociated.
 3. The process of claim 2, wherein saidpolymer stems from a monomer having a negative charge, said monomerselected from the group consisting of vinyl compounds having a carboxylgroup, vinyl compounds having an ammonium salt or metal salt of acarboxylic group, vinyl compounds having a sulfonic acid group, andvinyl compounds having an ammonium salt or metal salt of sulfonic acid.4. The process of claim 2, wherein said polymer stems from a monomerhaving a positive charge, said monomer being a member selected from thegroup consisting of vinyl compounds having a basic nitrogen atom andvinyl compounds having a nitrogen atom of a quaternary salt.
 5. Theprocess of claim 2, wherein a water-soluble addition-poly-merizablevinyl monomer carrying no charge may be used in combination with thecharged monomer serving as the polymer image precursor.
 6. The processof claim 5, wherein said water-soluble addition-polymerizable vinylmonomer is a member selected from the group consisting of acrylamide,N-hydroxymethyl acrylamide, methacrylamide, methyl methacrylate,vinylpyrrolidone, N,N-methylenebis (acrylamide), triethylene-glycoldimethacrylate, and polymethyleneglycol dimethacrylate.
 7. The processof claim 2, wherein said dye is an acid dye and a member selected fromthe group consisting of Acid Yellow No. 7, Acid Yellow No. 23, Acid RedNo. 1, Acid Red No. 52, Acid Blue No. 9, Acid Blue No. 45, Acid Blue No.62, and Acid Violet No.
 7. 8. The process of claim 2, wherein said dyeis a basic dye and a member selected from the group consisting of BasicYellow No. 1, Basic Yellow No. 2, Basic Red No. 1, Basic Red No. 2,Basic Blue No. 25, Basic Violet No. 3, and Basic Violet No.
 10. 9. Theprocess of claim 1, wherein said compound is a member selected from thegroup consisting of catechol, 4-methylcatechol, 4-t-butyl catechol,pyrogallol, methyl gallate, pyrogallol red, o-aminophenol, amidol,2-aminoresorcinol, o-phenylenediamine, tolyene-3, 4-diamine,1,2,4-triaminobenzene and alizarine.
 10. The process of claim 1, whereinthe high molecular weight material maintained in the silver halideemulsion layer is gelatin.
 11. The process of claim 1, wherein the highmolecular weight material maintained in the silver halide emulsion layeris a member selected from the group consisting of polyvinyl alcohol,polyvinyl pyrrolidone, polyacrylamide, carboxymethyl cellulose,cellulose oxyethyl ether, and dextran, or mixtures of the same withgelatin.
 12. The process of claim 1, wherein said sulfite ion stems froma precursor selected from the group consisting of an alkali metal,ammonium sulfite, an alkali metal bisulfite, and ammonium bisulfite. 13.The process of claim 1, wherein said sulfite ion stems from a precursorcapable of yielding sulfite ions upon hydrolysis, said precursor being amember selected from the group consisting of pyrosulfites of alkalimetals, ammonium pyrosulfites, and adducts of bisulfites with aldehydes.14. The process of claim 13, wherein said aldehyde is a member selectedfrom the group consisting of formaldehyde and glyoxal.
 15. The processof claim 1, wherein said sulfite ion is present in an amount greaterthan 0.05 mole per liter of reaction system.
 16. The process of claim 1,wherein said sulfite ion is present in an amount greater than 0.2 moleper liter of reaction system.
 17. The process of claim 1, wherein saidvinyl compouNd is a member selected from the group consisting ofacrylamide, acrylonitrile, N-hydroxymethyl-acrylamide, methacrylic acid,acrylic acid, calcium acrylate, sodium acrylate, ethyl acrylate,vinylpyrrolidone, vinylmethyl ether, vinylbutyl ether, vinylisopropylether, vinylisobutyl ether, vinyl butyrate, 2-vinylpyridine,4-vinylpyridine, 2-methyl-N-vinyl imidazole, potassium vinylbenzenesulfonate, and vinyl carbazole dicyclopentadiene methacrylate.
 18. Theprocess of claim 1, wherein said vinyl compound is a member selectedfrom the group consisting of N,N''-methylene-bisacrylamide, ethyleneglycol dimethacrylate, diethylene glycol dimethacrylate, triethyleneglycol dimethacrylate, polyethylene glycol dimethacrylate, divinylether, divinyl benzene, bisphenol-A-dimethacrylate,butylene-di-methacrylate, and pentaerythritol tetraacrylate.
 19. Theprocess of claim 1, wherein said process is carried out at a pH ofgreater than about
 6. 20. The process of claim 1, wherein said processis carried out at a pH of greater than
 7. 21. The process of claim 1,further comprising the presence of a thermal polymerization inhibitingamount of a thermal polymerization inhibitor.
 22. The process of claim21, wherein said inhibitor is a member selected from the groupconsisting of p-methoxyphenol, hydroquinone, alkylhydroquninone, and2,6-di-t-butyl-p-cresol.
 23. The process of claim 21, wherein saidpolymerization inhibitor is present in an amount of from 10 ppm to 1/00ppm of the weight of said vinyl compound.
 24. The process of claim 1,wherein said vinyl compound is present in an amount of from 1/30 to 30times the weight of the high molecular weight material of the silverhalide emulsion.
 25. The process of claim 24, wherein the vinyl compoundis present in an amount of from 1/4 to 4 times the weight of the highmolecular weight material of the silver halide emulsion.
 26. The processof claim 1, wherein said silver halide is present in an amount of 1/20to 2 times the weight of the high molecular weight material of thesilver halide emulsion.
 27. The process of claim 26, wherein said silverhalide is present in an amount of from 1/10 to 1/2 times the weight ofthe high molecular weight material of the silver halide emulsion. 28.The process of claim 1, wherein said compound is present in an amount offrom 1/1000 to 20 moles per mole of silver halide.
 29. The process ofclaim 1, wherein said compound is present in a processing solution, in aconcentration of from 1/10,000 to 3.0 moles per liter of solution. 30.The process of claim 29, wherein said concentration ranges from 1/3000to 1 mole per liter.